New Lead Acid Batteries; Charge & Monitor Upgrade?

[markopolo]

If batteries are used lightly & somewhat adequately cared for then I think having them around for a decade or so is not unusual. They'd be expected to have lost a fair amount of capacity though. If used lightly & well cared for then the capacity loss would be less.

I'm not certain if you can get a battery fully charged by charging it at a voltage in the float range. I used to think that it would eventually get fully charged. I still think that you can somewhat make up for otherwise less than perfect charging by keeping the batteries on a float charge.

PD has this to say:

If a lead acid battery is not immediately recharged, the lead sulfate will begin to form hard crystals, which can not be reconverted by a standard fixed voltage (13.6 volts) battery converter/charger.

and this:

This build-up will continue after each recharging cycle and gradually the battery will begin to loose capacity to store a full charge and eventually must be replaced.

The article is here: https://www.progressivedyn.com/service/battery-basics/ - I can't say that I agree with all they have to say. I disagree with 12.6V being a fully charged battery and also with charging at 14.4V only to 90% for example. I'm comfortable with going to 100% at 14.4V based on ending amps then switching to float.

My current thinking is that you need to keep the batteries in the 14.4V absorption stage until the current flow is in the 1A to 2A range (adjusted for battery bank size) to reconvert as much of the lead sulfate as possible.

[booster]

I think that sums up what I had been thinking also for a while. The biggest questions in my mind have been the cutoff point on the amps based charging as we don't really know if taking them all the way to the "not changing" point in amps to the batteries is better or worse. It takes and extra 4+ hours to get there and that extra time at full charge voltage may not be good. Of course it is also hard to control automatically because the amps vary a bit time to time because of temp, etc. The other big question has been if continuous float is good or some other method or combination of things? PD does a periodic full voltage routine, for instance. Is it better to occasionally do a 20% discharge and recharge once in a while? It is probable that just using the recommended amps % is close enough to not make a very big difference in life, but we never have heard how they got that number. The as soon as possible recharge and getting a completely full recharge quickly are probably the really big issues with most systems.


One thing that is kind of weird and interesting, maybe, that I have noticed a couple of times sinces we put the batteries under the van where they see bigger temp swings is that the temp controlled charging systems will occasionally turn themselves down further than the battery voltage so we see a discharge while the chargers are still running in float.


Seeing that happen kind of makes me wonder what would the affect on the battery be if there were no load on the battery to allow the discharge. Would the temp increase then mean that the battery voltage would be too high and be a potential problem similar to a too high float voltage? Could this be part of why they say to store in cool areas when disconnected/

[markopolo]

I looked at an old log of my Samlex inverter/charger in a timer based (not the ending amps) mode. It held the batteries at 14.4V for an extra 3hrs after getting to 2A in and only reduced acceptance down to 1.6A-1.5A (the "not changing" point). In that example, there was likely no point in holding the batteries at 14.4V for the 3 extra hours. It probably did more harm than good.

I haven't seen temperature compensation adjustment go below the voltage of the battery but I only have temperature compensation on one RV and there's a lot of open space around those batteries.

In the middle of winter though the temperature compensated high voltages can look scary but I've decided to trust the system.

I don't have temperature compensation on the van so I manually compensate by triggering a 0.4V drop across all modes. That results in a 12.8V summer float and 14.0V boost while plugged in. It's not the best but the under the hood wet cell is probably 10 years old and spit up a bit of electrolyte a couple of years ago at standard settings. I think it was caused by a combination of boost mode and high summer temperatures on an old battery. I switch back to normal settings in the fall. The charger is on normal setting for at least 3/4 of the year.

[peteco]

Hey Booster, did you ever get from Tripplite the detailed RV750ULHW charging specs? Or did you ever figure them out or measure them on your own?

Also, I see mention of temperature compensation feature as optional. It is hard to tell if the RV750ULHW actually has this capability, and if so what temperature sensor is needed. Did you ever investigate this option?

[booster]

Originally Posted by peteco

Hey Booster, did you ever get from Tripplite the detailed RV750ULHW charging specs? Or did you ever figure them out or measure them on your own?

Also, I see mention of temperature compensation feature as optional. It is hard to tell if the RV750ULHW actually has this capability, and if so what temperature sensor is needed. Did you ever investigate this option?

Tripplite used to list the specs in the owners manual for voltage and IIRC for the wet cell setting it was 14.3 or 14.v absorption and 13.5v float. They don't show them anymore and from what we have heard won't tell you anything about the charge profile or times.


When we had the Tripplite, it was very early in the learning curve for me, so really didn't understand what was going on very well at all, and the results were quite confusing. Also had no monitor so was doing all the SOC stuff with specific gravity on wet cells.


We had some discussions on it here, so I may be able to find them to refresh my memory, but the big thing I remember was never being able to get the batteries full after a charging cycle as it would leave them at about 85% or 90%. I also was unable to get it to do a another absorption charge right away as it would go right to float. I had heard that it checked voltage to determine if to do a charge cycle, so I turned on enough things to lower the voltage but it would still not stay in absorption. This may be because it was unknown then, at least to me, that the Tripplite may do it based on hitting about 10 amps of charging current that Marko has mentioned recently. At the time we had two SCS200 Trojan 12v wet cells so 230ah total.



When it did run a full cycle, it appeared to max out at 4 hours of absorption consistently if the batteries were low enough at the start,so it likely had a 4 hour maximum absorption timer in it. The idea of long term float to finish the charge was not anything I remember ever being considered back then, so I was always checking SOC right after the charge cycle or before charging, not after days and days of float.


I don't think the Tripplite 750 has the temp comp option on it like some of the larger versions do, but Marko probably knows. I don't recall ever specifically looking for it as I felt we needed a better charger to get fully charged anyway. We went to the Blue Sea shortly after we increased battery bank size to two 260ah 6 volt GC2 Trojan wet cells, plus one of the SCS200 wet cells, as the Tripplite left them at even lower SOC and the mismatch of batteries needed multibank charging. We didn't even know about using amps to end charging when I got the Blue Sea, but it did control that way and had temp compensation, so it was able to get the batteries full regularly.

[markopolo]

I'm still super curious to find out if the High/Low (Fast/Slow) amp setting on the Tripp Lite affects when the absorption phase flips over to float.

Booster tried a lot of stuff years ago - http://www.classbforum.com/forums/f5...gers-2738.html - but I don't think he tried the low amp setting.

I think it is a possibility because it would make little sense to have an 11 amp charger (low or slow setting) that flips to float at 10 amps. I'll keep my fingers crossed that someday, someone tests the Low setting and discovers that the switch to float amperage is proportional to the amp setting.

Discovering proportional float amperage on the Tripp Lite may end up being wishful thinking on my part but fingers crossed that it isn't.

[booster]

Originally Posted by markopolo

I'm still super curious to find out if the High/Low (Fast/Slow) amp setting on the Tripp Lite affects when the absorption phase flips over to float.

Booster tried a lot of stuff years ago - http://www.classbforum.com/forums/f5...gers-2738.html - but I don't think he tried the low amp setting.

I think it is a possibility because it would make little sense to have an 11 amp charger (low or slow setting) that flips to float at 10 amps. I'll keep my fingers crossed that someday, someone tests the Low setting and discovers that the switch to float amperage is proportional to the amp setting.

Discovering proportional float amperage on the Tripp Lite may end up being wishful thinking on my part but fingers crossed that it isn't.

It would be interesting to see, and could be of benefit in getting the batteries full, as it would give a transition amps of about 2.5 amps if the ratio was the same as at 45 amps. Of course, as many of us have learned the hard way over time, when the transition amps get that low, and are measured in the charger not at the batteries, you get very heavy influences from any loads that are on and can get locked into absorption too long unless on a timer also. It would also be of interest to see if the the 4 hour timer that is probably in the Tripplite would still be used at 11amps. It likely would be, so that would severely limit the amount of recharge AH you could get. Probably would be best to run a charge cycle at 45 amps, and then if you could get it to restart in absorption again run one at 11 amps. PITA, but might be effective for the non daily need to get full batteries.


On edit, went back and read the old posts linked by Marko (thanks for digging it out). Very interesting that the 10 amps of load came in to play for getting absorption to start, but that higher load didn't seem to hold it in absorption very long. Knowing what we know now and seeing the old data is interesting and makes more sense now.


I think with the Tripplite we may be looking at some combination of timers, algorithm and maybe the 10 amps all interacting in some hard to determine way. This is a very early designed smart charger so could be very different from current ones in how things are done.


One guess is that it runs bulk pretty much as long as it takes to get to the 14.4v setpoint for absorption and then runs 4 hours or until it gets to 10 amps of current (including loads), for instance. It may well be doing other stuff with calculating the absorption max time, so less than 4 hours depending on where the battery started for voltage and/or amps.



Based on what we saw back then, I do think it is very hard to get a Tripplite to charge consistently to full, even with tricks. It would be interesting to rerun some of those old tests with it on a battery monitor so we could see all of what is happening during charging.

[peteco]

Originally Posted by markopolo

I'm still super curious to find out if the High/Low (Fast/Slow) amp setting on the Tripp Lite affects when the absorption phase flips over to float.

Booster tried a lot of stuff years ago - http://www.classbforum.com/forums/f5...gers-2738.html - but I don't think he tried the low amp setting.

I think it is a possibility because it would make little sense to have an 11 amp charger (low or slow setting) that flips to float at 10 amps. I'll keep my fingers crossed that someday, someone tests the Low setting and discovers that the switch to float amperage is proportional to the amp setting.

Discovering proportional float amperage on the Tripp Lite may end up being wishful thinking on my part but fingers crossed that it isn't.

OK, I just switched the Tripplite to the 11 amp setting and ran a charging test. I measured the voltage and specific gravity before starting: Battery 1: 6.36v, SG: 1.260/1.260/1.250. Battery 2: 6.35v: SG: 1.260/1.260/1.260. Not sure if the slightly low cell is a problem. Will check again after charging.

I realized after I started that the separator had the chassis battery connected. So I disconnected the chassis battery using the separator disconnect function at 35 minutes.

Interesting that the peak 14.4 charge voltage held for over 30 minutes, whereas on the 45 amp charge setting it only held for about a minute. I think this behavior is what Marco was anticipating. At 14.4 volts the electrolyte was bubbling noticeably.

I left it charging overnight and will check again in the morning.

[booster]

Originally Posted by peteco

OK, I just switched the Tripplite to the 11 amp setting and ran a charging test. I measured the voltage and specific gravity before starting: Battery 1: 6.36v, SG: 1.260/1.260/1.250. Battery 2: 6.35v: SG: 1.260/1.260/1.260. Not sure if the slightly low cell is a problem. Will check again after charging.

I realized after I started that the separator had the chassis battery connected. So I disconnected the chassis battery using the separator disconnect function at 35 minutes.

Interesting that the peak 14.4 charge voltage held for over 30 minutes, whereas on the 45 amp charge setting it only held for about a minute. I think this behavior is what Marco was anticipating. At 14.4 volts the electrolyte was bubbling noticeably.

I left it charging overnight and will check again in the morning.

It does not appear to have gone to float on amps, though, at least not at the same ratio as in 45 amp range.


What is very interesting, and may explain both 11 and 45 readings if it means anything is that the absorption time is nearly identical to time it was in bulk. Perhaps they are just setting the absorption time to whatever the bulk time runs?

[markopolo]

Thanks for doing that Pete. I know how time consuming those type of tests are. I think that you've confirmed that the Low or Slow setting will put a bit more of a charge into the batteries.

I think I interpret the new chart as Booster did. It started in bulk mode supplying the full 11A but that wasn't enough current to raise the voltage rapidly. The 11A output was being split between house and chassis batteries. The voltage slowly increased and when the chassis battery was taken offline, the new house batteries had plenty of charging current available and quickly got up to 14.4V. It held 14.4V longer than it would have at the High or Fast setting. Transition to float occurred at some point after 5.8A

IMO, transitioning to float at 5.8A or so is better than at 10A (meaning that more of the lead sulfate should get converted back to lead and sulfuric acid).

Booster described usage of that feature well:

Probably would be best to run a charge cycle at 45 amps, and then if you could get it to restart in absorption again run one at 11 amps.

You don't need to run both cycles every time as he also pointed out.

If the Blue Sea separator was left on then the two new house batteries might be held at 14.4V until about 4A or a bit less with the remainder going to the chassis battery. 4A would be even better IMO.

I think the Low or Slow setting will be useful to a lot of folks who want to take just a bit better care of their batteries without any additional expense.

[booster]

I think the biggest question is if it was the chassis battery in the system extending the bulk stage that made the absorption last longer, or if it did trigger at the particular voltage, or did it trigger based on the fact that the amps were no longer dropping (I missed that at first look at the chart)?


Interesting stuff for sure, thanks for collecting the data!

[markopolo]

My guesses (if I understand your question/observation correctly):

- I'd say yes, the chassis battery in the mix extends both the bulk and absorption phases.
- the switch to float is being caused when reaching a current flow set-point.

It appears to be all about current and voltage (maybe time factors in but not observable in these tests):
Max current (as per switch setting, low 11A or high 45A) until 14.4V reached, then hold at 14.4V until absorption current drops to setpoint (as per switch setting, low 5.8A (or so) or high 10A) then the switch to float occurs.

I don't think it's doing an unchanging amps transition. It is possible though but I'd expect it to hold at the unchanging amps for longer than a few minutes.

[booster]

We do know from other chargers that they do an algorithm calculation for absorption time based on starting amps and volts and IIRC some even explained that the calc at startup was to have the charger take a guess at how big the battery bank is and how far it is discharged which allowed them to chose an appropriate absorption time. I think Sterling explains it, or used to anyway, and it appears that this is what our little Ctek does. I don't recall them saying they look at amps at the end of absorption, but the certainly doesn't mean they don't, either.


We also know that more recent designs include, sometimes settable in fixed increments, transition amps which also appear to be on top of an algorithm, so maybe the older units like the Tripplite have also used amp all along, but as a fixed number that was never mentioned.


Of course, with all of the internally measured amps units, loads mess up the accuracy, so they have to make the setting much higher than would be ideal. There are very few that control the transition to float by reading the amps to the batteries only. I can think of about 3 that I know of, but there may be more that we haven't seen.


If the Tripplite really is going to float at 10 amps consistently you should be able to turn on a 10 amp load to get it to stay in absorption until the maximum time on the absorption timer, which I think is 4 hours (typical setting for many chargers). I don't recall if I left the load on when I tested adding load to get the Tripplite to do a full charge cycle on our old setup. It is very likely I shut the load off once the charger started charging, which might explain why load didn't do much for me.

[markopolo]

Originally Posted by booster

................................
Of course, with all of the internally measured amps units, loads mess up the accuracy, so they have to make the setting much higher than would be ideal. There are very few that control the transition to float by reading the amps to the batteries only. I can think of about 3 that I know of, but there may be more that we haven't seen.

...............................

I know I couldn't figure out how that was done when you first mentioned probably a few years ago now. Maybe later I understood it but now, once again, I can't figure out how the charger distinguishes between load amps and charging amps.

Do those chargers subtract the out amps from the in amps and change settings based on net amp flow?

[booster]

Originally Posted by markopolo

I know I couldn't figure out how that was done when you first mentioned probably a few years ago now. Maybe later I understood it but now, once again, I can't figure out how the charger distinguishes between load amps and charging amps.

Do those chargers subtract the out amps from the in amps and change settings based on net amp flow?

The chargers that measure only charging amps are actually simpler than the algorithm and/or internal measuring chargers, as they just directly measure the amps that control the charging profile at the batteries with a shunt, just like a battery monitor does. Most also include a battery monitor in the remote for the charger, too, so they can also be set to control of amp hours returned, but that is inaccurate due to charge efficiency variations.


With the amps measured directly at the batteries, the control for charging doesn't need to even look at total amps out of the charger or any amps being generated by other charging sources like solar or alternators. Most still have a much less accurate amp measuring within the charger to use for controlling output % and such, but it not used for controlling the charging proper.


Our Magnum 100 amp charger can be putting out nearly full output to run loads and still control the battery charging to within it's one amp increment (wish it was in 1/10 amp) setting, as long as the charger can maintain 14.3v. It is also very slick that the Magnum will stay in absorption as long as the battery amps are not below the setting, even if those amps are coming from the solar. It is really weird to see the Magnum in absorption mode and voltage with essentially zero amps leaving it.



Besides Magnum, it appears that the centrally controlled Victron systems, probably Outback, control off the battery amps. You can make a Blue Sea charger do similar by adding a simply relay switching circuit to the loads as the Blue Sea has 3 independent banks that allow you to take the loads off the battery charging.

[peteco]

I need to accept the fact that the Tripplite will not fully charge the batteries. The previous batteries probably had excessive sulfation from undercharging that led to bulging and the crack in the case. How the batteries still managed to perform well is a mystery. Credit to Deka for a well made battery.

Handybob is high on the Magnum MMS1012 inverter charger, which would run over $1000 with the monitor to adjust parameters. I also need to install a BMS.

https://handybobsolar.wordpress.com/...-other-things/

What other chargers (hopefully cheaper) should I consider?

[dicktill]

Originally Posted by peteco

I need to accept the fact that the Tripplite will not fully charge the batteries. The previous batteries probably had excessive sulfation from undercharging that led to bulging and the crack in the case. How the batteries still managed to perform well is a mystery. Credit to Deka for a well made battery.

Handybob is high on the Magnum MMS1012 inverter charger, which would run over $1000 with the monitor to adjust parameters. I also need to install a BMS.

https://handybobsolar.wordpress.com/...-other-things/

What other chargers (hopefully cheaper) should I consider?

Hi Pete,

I have a Magnum MM1212 inverter-charger that might be your answer ... we can talk off-line if you wish.

Regards, Dick

[rowiebowie]

Originally Posted by dicktill

Hi Pete,

I have a Magnum MM1212 inverter-charger that might be your answer ... we can talk off-line if you wish.

Regards, Dick

I've been following this thread as I have the Tripp Lite 750 in my '2012 class b with compressor fridge. I put two new flooded batteries in after I purchased mine. I was very pleased for the first year, but after 13 months they no longer hold a full charge. They now want to rest at 12.45 volts after a day or so off the charger.

I've regularly checked fluid and topped out with distilled water (but they never needed much). I never ran them down past 12.2 volts, never went more than two weeks between topping out the charge, and used the equalizer feature every few months. I have no significant problem with parasitic drains.

On a recent trip, the batteries would go to 12.0 volts overnight, whereas before they never went down past 12.2 volts. And now the equalizer feature seems to only run a few minutes and only initiates if I also have the "higher charge" dip switch engaged when I start the equalize cycle.

I've been watching this thread and now wonder if I need to replace the Tripplite. Will the money flow never cease?

[peteco]

Originally Posted by rowiebowie

I've been following this thread as I have the Tripp Lite 750 in my '2012 class b with compressor fridge. I put two new flooded batteries in after I purchased mine. I was very pleased for the first year, but after 13 months they no longer hold a full charge. They now want to rest at 12.45 volts after a day or so off the charger.

I've regularly checked fluid and topped out with distilled water (but they never needed much). I never ran them down past 12.2 volts, never went more than two weeks between topping out the charge, and used the equalizer feature every few months. I have no significant problem with parasitic drains.

On a recent trip, the batteries would go to 12.0 volts overnight, whereas before they never went down past 12.2 volts. And now the equalizer feature seems to only run a few minutes and only initiates if I also have the "higher charge" dip switch engaged when I start the equalize cycle.

I've been watching this thread and now wonder if I need to replace the Tripplite. Will the money flow never cease?

My experience is similar, but with a few differences.

I was never able to get the equalizer function to work on the Tripplite despite trying various switch settings.

Last fall I boondocked for 3 days without running the engine and the batteries went down to about 12.0v. I had a refrigerator vent fan running almost all the time along with lights (LED), water pump, and occasional roof exhaust fan. So I was pleased with that. I have no idea how many Amp-hrs I used.

Are your batteries bulging? Can you see any buildup on the plates?

[rowiebowie]

Originally Posted by peteco

My experience is similar, but with a few differences.

I was never able to get the equalizer function to work on the Tripplite despite trying various switch settings.

Last fall I boondocked for 3 days without running the engine and the batteries went down to about 12.0v. I had a refrigerator vent fan running almost all the time along with lights (LED), water pump, and occasional roof exhaust fan. So I was pleased with that. I have no idea how many Amp-hrs I used.

Are your batteries bulging? Can you see any buildup on the plates?

My batteries (Duracell deep cycles from Sam's Club) are not bulging and from all outward appearances look new when I wipe them down. I haven't really paid attention to the plates. No reason to until now, but before our next trip, I'll probably be replacing them. If they look bulged or sulfated, then I guess a replacement for my Tripp Lite will be next.

Problem then, is do I start the ball rolling down hill and add two battle born lithiums, a DC to DC charger, and additional solar? Voila, $3500 later.